Anthropogenic global warming is causing rapid deoxygenation of the modern oceans, threatening marine ecosystems. The multiple episodes of oceanic anoxic events (OAEs) that occurred during geological history provide a crucial perspective for understanding their mechanisms and consequences. This paper presents the classification system of ocean redox states (from oxic to euxinic), and summarizes the different indicators used for paleo-redox reconstructions such as lithofacies, biofacies, minerals, redox-sensitive elements, isotopes, and biomarkers. Based on the 30 studies in this special issue, we synthesize the following advances: (1) spatio-temporal evolution of ocean anoxia from the Cambrian to the Late Paleozoic and its coupling with the carbon and nitrogen cycles; (2) triggering and driving roles of volcanic activity, climate fluctuations, and enhanced weathering on OAEs; (3) responses of biota to OAEs, including extinction, recovery, and community reorganization; (4) responses of terrestrial ecosystems to OAEs, such as vegetation turnover and increase of lacustrine organic carbon burial; and (5) the modulating role of astronomical orbital cycles (especially eccentricity) on organic matter burial during OAEs. These multidisciplinary results deepen our understanding of the mechanisms and ecological responses of deep-time OAEs and provide geological analogues and theoretical baselines for assessing the future trends of modern ocean deoxygenation.

The Cretaceous Oceanic Anoxic Event 2 (OAE 2, ca. 94 Ma) is one of the most significant carbon cycle perturbations during the Mesozoic Era. It is widely considered to have been triggered by large igneous provinces (LIPs) volcanism. However, quantifying the pattern and magnitude of LIPs volcanic activity remain insufficiently understood. Here, we model sedimentary mercury enrichment and mercury isotope variations across OAE 2 to quantitatively evaluate the LIPs volcanism. Our global oceanic Hg box modeling results suggest an 8-16-fold increase (similar to 2480-4960 Mg yr(-1)) in volcanic Hg inputs to the atmosphere and ocean in the lead-up to the OAE onset. The global Hg enrichment factor (Hg-EF) data exhibit spatial heterogeneity during OAE 2. The lack of globally uniform Hg enrichment underscores the complex interplay between volcanism style (submarine vs. subaerial), paleogeographic isolation, and proximity to LIPs during OAE 2.

Oceanic Anoxic Event 2 (OAE2, ∼94 Ma) is a global Earth-system perturbation associated with extensive marine oxygen loss and enhanced burial of organic carbon in marine sediments. Sulfur cycling links carbon remineralization, nutrient regeneration and redox stability, but the drivers of sulfur isotope variability during OAE2 remain poorly constrained, partly because existing records are geographically biased toward Northern Hemisphere basins. Here we present a high-resolution pyrite sulfur isotope (δ34Spyr) record from the Qiangdong section in southern Tibet, providing a Southern Hemisphere perspective on sulfur cycle dynamics during OAE2. The data reveal four distinct intervals of δ34Spyr evolution, indicating rapid and large perturbations to the marine sulfate reservoir. A pronounced positive excursion in δ34Spyr prior to OAE2 reflects contraction of the local sulfate pool, most plausibly driven by methane seepage and intensified anaerobic methane oxidation. This is followed by an abrupt negative shift during OAE2 that is inferred to reflect renewed sulfate input associated with intensified volcanic activity. Subsequent recovery toward background values marks progressive stabilization of the sulfur cycle as volcanic forcing waned and pyrite burial increased. Comparison with globally distributed records shows that sulfur isotope evolution during OAE2 was governed by the interplay between global volcanic forcing and regional depositional processes, rather than by oxygen depletion alone. These results highlight dynamic sulfate reservoir perturbations as a key mechanism linking volcanism, methane release and large-scale ocean anoxia.

Calcareous nannofossils are abundant and globally distributed fossils that are widely used in the study of stratigraphy and palaeoclimate. A large number of nannofossil data have been generated over the past several decades, but the information is distributed across the published scientific literature in a wide variety of formats, and data compilation has focussed on the Cenozoic. In Cretaceous marine sediments, nannofossils are a key group of microfossils, and they have been extensively studied for both biostratigraphy and palaeoceanography. However, only a fraction of these data have been compiled. In order to exploit this archive of palaeontological information, we have (1) extended the capabilities of the Mikrotax database system to allow compilation of occurrence data, (2) tested this by compiling a large set of Cretaceous nannofossil occurrence records (Uneptune database), and (3) developed a suite of tools for displaying these data on the Nannotax database system, including biogeographic maps, time-latitude plots, and occurrence frequency range charts. For the Uneptune database, we selected a range of published high-quality Cretaceous nannofossil datasets, screening the data to standardise the taxonomy and revise the age models where appropriate. The resulting database includes around 7000 samples, 500 species, and 175 000 occurrence records, which is 3 times the size of the previous largest Neptune Cretaceous database.

Chemical weathering is a critical Earth system process that regulates climate, ocean chemistry and the long-term carbon cycle. However, the intensity and variability of chemical weathering remain insufficiently constrained for the mid-Proterozoic (similar to 1.8-0.8 Ga), greatly limiting our understanding of the environmental context to early eukaryotic evolution. Here, we report the first coupled positive seawater Sr-87/Sr-86 (similar to 0.0007) and delta Li-7 (similar to 5 parts per thousand) isotope excursions of the Mesoproterozoic Era (1.6-1.0 Ga), which we argue signifies a substantial weathering event at similar to 1.57 Ga, characterised by increased silicate weathering rates and decreased weathering congruency. Drawing on independent geological evidence, we posit that enhanced volcanic CO2 degassing, possibly alongside accretional orogenesis, increased denudation rates and invigorated the hydrological cycle, amplifying silicate weathering and secondary clay formation. This weathering pulse broadly coincided with coeval ocean oxygenation and carbon cycle disruption, implicating it in the appearance of the earliest known decimetre-scale, multicellular eukaryotic fossils.

Intensified frequency and scale of wildfires due to global warming has been increasingly recorded in recent years. Studies of wildfire activity during deep time greenhouse climate states are crucial for evaluating their likely impacts on the global environment and ecosystems in the future. Oceanic anoxic event 2 (OAE 2, similar to 94 Ma), which was characterized by extremely high global temperature and a reduced equator-pole temperature gradient, could provide insights into our understanding of present-day global change processes. Here we provide data on polycyclic aromatic hydrocarbon (PAH) abundance from the Qiangdong section in the Tethyan Himalaya of southern Tibet to investigate wildfire behavior and its impact on the environment during OAE 2. Our results indicate a significant increase in the frequency of wildfires during the early part of OAE 2, followed by a rapid weakening. The change of PAH composition through OAE 2 in Qiangdong shares a similar trend to that previously found in the Western Interior Seaway (North America), indicating potentially globally elevated wildfire frequency during the early part of OAE 2. We also document a rapid increase in chemical index of alteration values in Qiangdong. These data, coupled with other proxies for weathering intensity through OAE 2, suggest that increased weathering during OAE 2 can be attributed at least in part to the effects of vegetation loss caused by wildfire. As such, we suggest that frequent wildfires during OAE 2 promoted the flux of nutrients to the oceans, thereby stimulating productivity that, in turn, increased the area of oceanic anoxia and organic carbon burial.

Chemical weathering is a critical Earth system process that regulates climate, ocean chemistry and the long-term carbon cycle. During the mid-Proterozoic (~1.8‒0.8 Ga), chemical weathering is generally considered to have been relatively muted, but this perception remains largely untested, limiting our understanding of the drivers of purported oxygenation events and coeval biological evolution. Here, we report the first coupled positive seawater 87Sr/86Sr (~0.0007) and δ7Li (~5‰) isotope excursion of the Mesoproterozoic Era (1.6‒1.0 Ga). Geochemical box modelling suggests the concurrent Sr - Li isotope excursions signify a substantial weathering event at ~1.57 Ga, characterised by increased silicate weathering rates and decreased weathering congruency. Drawing on independent geological evidence, we posit that enhanced volcanic CO2 degassing, possibly alongside accretional orogenesis, increased denudation rates and invigorated the hydrological cycle, amplifying silicate weathering and secondary clay formation. This weathering pulse coincided with the ocean oxygenation and carbon cycle disruption, implicating it in the coeval preservation of the earliest known decimetre-scale, multicellular eukaryotic fossils.

The Cretaceous Oceanic Anoxic Event 2 (OAE2,-93.9 Ma) was a period of rapid global environmental change and one of the warmest intervals in the Phanerozoic. Despite its global significance, we still know little about the effects of this greenhouse event from the shallow marine shelf environments of the Southern Hemisphere. Here, we present a paleoenvironmental reconstruction from the eastern Tethys Ocean based on calcareous nannofossil paleoecological records from an OAE2 section (Qiangdong) in southern Tibet. Our nannofossil temperature index indicates onset of warming ca. 75 kyrs before the OAE2, peaking in the early OAE, but followed soon (-60 kyr after the OAE onset) by a phase of climatic instability. This cool interval correlates well with the Plenus Cold Event (PCE), previously documented in the Northern Hemisphere (e.g., western Europe). The PCE cooling is followed by further warming in the later OAE, continuing into the post-OAE2 early Turonian interval consistent with peak warmth of the Cretaceous thermal maximum (KTM). A calcareous nannofossil productivity index reveals dynamic surface water productivity trends with maximum values during the PCE cool interval indicating that sequestration of CO2 through elevated marine primary productivity was likely an important feedback during this carbon cycle perturbation event.

To safely store CO2, it is necessary to accurately predict the behaviors and trapping evolution of CO2 in saline aquifers. However, due to the heterogeneity of actual saline aquifers, the evolution of CO2 plume and accompanying trapping are still unclear during and after injection. Although prior studies have highlighted the impact of capillary entry pressure heterogeneity on CO2 plume and trapping, the role and influence of CO2-induced geochemical reactions are still not fully understood. Therefore, the main objectives of this work are to study the evolution of CO2 plume and storage under heterogeneous capillary entry pressure and geochemical reactions. To illustrate the evolution, a comprehensive CO2 migration and storage model under heterogeneous capillary entry pressure and geochemical reactions is done to study CO2 behavior in detail. The results showed that heterogeneous capillary entry pressure in the saline aquifer can hinder the upward migration of CO2, causing it to redirect and increase its lateral volume. The geochemical reactions can reduce porosity by 10-4 and permeability by 1 mD within 100 years and hinder CO2 migration in all directions. The capillary entry pressure magnitude, its heterogeneity, and lateral correlation length are the main parameters affecting the evolution of CO2 storage. Their increase can greatly limit CO2 vertical migration rates and decrease dissolution and mineral trapping amount but may double local capillary trapping amount. In contrast, the increase in temperature and the ratio of vertical/horizontal permeability favors CO2 vertical migration, dissolution, and mineral trapping amount. Therefore, to ensure the long-term safety of CO2 storage, it is necessary to select a suitable heterogeneous reservoir.

Over the past six decades, the scientific ocean drilling (SOD) programs have collected vast and invaluable data for Earth history research. However, the scattered state of these data across multiple repositories, along with inconsistent standards, methodologies, and terminologies, have increased the complexity of data processing and posed barriers to its effective utilization. While several databases have been developed to consolidate and improve access to SOD data, each has limitations in scope. To address these challenges, we introduce the Sediment Spatial and Temporal Database (SedST, http://sedst.org), a new platform designed to aggregate chronological data from the extensive archives of SOD, including postcruise literature, and provide tools for data accessibility. SedST standardizes biostratigraphic, magnetostratigraphic, and radiometric dating records, aligning them with the latest Geologic Time Scale 2020, to ensure consistency and coherence. Employing the Bchron methodology, SedST establishes age-depth models for >1000 SOD boreholes. Presently, SedST encompasses 37,329 entries from 181 expeditions and 1300 holes, covering the world’s ocean basins and including records as old as the Late Jurassic. The platform provides powerful tools for sample ID to depth conversions and individual hole to composite site depth transformation. Accessible via user-friendly graphical interfaces, SedST simplifies data queries and allows the export of search results in CSV format. As a constantly developing platform under the umbrella of the Deep-time Digital Earth program, SedST is committed to enhancing the accessibility and discoverability of marine sediment data, fostering new insights into Earth’s geological history.

Variations in carbon isotope (delta C-13) values of Aptian marine strata are globally comparable and regarded as an important tool for the stratigraphic correlation of Aptian successions. The most remarkable feature of the delta C-13 curve of the Aptian is an abrupt negative excursion followed by a prominent positive excursion, which defines the early Aptian Oceanic Anoxic Event (OAE1a, similar to 120 Ma). However, a complete and precise OAE1a record from eastern Tethys has yet to be established. Based on previously investigated integrated biostratigraphy, we present a high-resolution lower Aptian delta C-13 curve from bulk organic carbon through an expanded succession at the Chaqiela section in the Tibetan Himalaya. The depositional environment, couple with TOC/TN data, indicate that the organic matter was predominately sourced from marine plankton. As such, our results provide a record of secular changes in the delta C-13 of the dissolved carbon pool of the shallow sea on the southern margin of eastern Tethys. The co-occurrence of glauconites and enrichments of the redox-sensitive trace elements (RSTEs) indicate largely suboxic bottom water conditions in the shallow marine eastern Tethys Ocean during OAE1a. Other paleoclimatic proxies suggest a relatively warm and humid paleo-environment during this time interval, with moderate to intense chemical weathering conditions revealed by chemical index of alteration (CIA) values.

During the Cretaceous, global ocean redox state fluctuated dramatically, resulting in the deposition of black shales and Cretaceous Ocean Red Beds (CORB). Herein, the chemical weathering intensity indexes calculated by major elements and the geochemical behaviors of rare earth elements (REE) were investigated in the late CORBs and the underlying shales deposited in southern Tibet and the Northern Atlantic. The original deposition environment of CORBs from both sites showed intensified chemical weathering extent under relatively warm and humid conditions, despite an overall global cooling trend during the late Cretaceous. The large variations of Ce anomalies (0.65-1.46) and LREE/HREE ratios (0.60-0.94) normalized by Post-Archean Australian Shale (PAAS) in the shale layers were the results of Fe mineral transformation, and the generally positive PAAS-normalized Eu anomalies (0.93-1.50) were likely controlled by the material sources. The CORBs displayed higher contents of total REE and Fe2O3 than the underlying shales, and had a similar covariant relationship with the chemical weathering intensity. This study suggested that a large amount of terrigenous iron was transported into the oxic Cretaceous Ocean by continental weathering, and REE fractionations were potential indicators to reflect sedimentary location and relatively sedimentation rate of ocean red beds formation across the Ediacaran and Phanerozoic.

The biotic, environmental, climatic, oceanic, and sea-level perturbations during the Early Aptian Oceanic Anoxic Event (OAE) 1a have been extensively documented from both deep- and shallow-marine deposits worldwide. However, there has been relatively little comparative assessment of the simultaneous interplay among organic carbon burial, redox conditions, terrigenous output, and productivity, leading to a lack of precise constraints on these relationships. Here, we use analyses of stable carbon isotopes (δ13Corg, δ13Ccarb, and Δ13C), total organic carbon (TOC), detrital proxies (Al, Si, Ti, K), redox-sensitive (RSTE: U, V, Mo) and productive-sensitive (PSTE: P, Cu, Ni) trace elements from a continuous, predominantly carbonate succession of the Kazhdumi Intrashelf Basin to evaluate the culprits for the OAE1a-associated changes in bottom-water oxygenation, organic-rich layer formation, and biotic shifts along the Arabian margin of the Neo-Tethys. Concentrations of Al-normalized RSTE and TOC values indicate that the bottom water conditions ranged from oxic prior to and at the onset of the OAE 1a (carbon-isotope segments C2 to basalmost C4 sensu Menegatti et al., 1998), to anoxic-suboxic but not euxinic (Mo < 25 ppm) during the lower C4 through C5 + C6 segments, and then returned to oxic-suboxic in the remaining C5 + C6 segment. The increase in Al-normalized PSTE coupled with TOC concentrations in the basal C4 is coeval with a change from predominantly orbitolinid-ostreid to planktic foraminifera-radiolarian biota. The periodically high productivity, driven both by the surface-water productivity as well as by phosphorus recycling from the sediments, continued through the C5 + C6 segments as evidenced by matching Si/Al and PSTE peaks (Cu/Al and Ni/Al). The study sheds new light on the causes of variations in bottom-water deoxygenation, organic content, nutrient availability, and biotic shifts in semi-restricted, relatively deep (>100 m), continental-margin basins during major oceanic perturbations.

The Aptian Dariyan (Shu'aiba) Formation is one of the major Cretaceous reservoirs in the Middle East. Despite its economic significance, an understanding of the influence of depositional facies and a sequence of diagenetic events on its reservoir quality remains limited. Here, we address this challenge through analysis (facies, petrophysics, geochemistry) of a continuous, ∼180 m thick core from NW Persian Gulf, and a fully-automated identification of hydraulic flow units (HFUs). Ten carbonate and four predominantly siliciclastic facies were identified as part of four facies associations, from shallowest to deepest: mixed tidal flats, inner ramp (lagoon and shoals), shallow open-marine mid ramp, and deep open-marine (outer ramp and intrashelf basin). The stacking pattern of facies yields five third-order transgressive-regressive sequences. Three hydraulic flow units (HFUs) were identified and evaluated against lithology and petrophysical values: baffle unit (HFU1), normal unit (HFU2), and permeable unit (HFU3). The permeable unit exhibits good storage capacity and moderate flow capacity. The data reveal an overall complex paragenetic and porosity-modification history of the Dariyan Formation. The overwhelmingly mud-dominated texture of the facies, along with meteoric-zone dissolution under a predominantly warm and humid greenhouse climate during periods of relatively low sea level, and subsequent fracturing during deep burial played a major role in controlling the reservoir quality.

The Late Triassic evolution of the Songpan-Ganzi Terrane in the eastern Tibetan Plateau is crucial for understanding the closure of the eastern Paleo-Tethys Ocean. However, the strong thickening and deformation of sedimentary cover make the Songpan-Ganzi geological records complicated and even obscured, impeding the reconstruction of regional tectonic evolution. In this study, we provide new geochemical data of detrital spinels from the Upper Triassic strata in the eastern Songpan-Ganzi Terrane to reveal the provenance and the regional tectonic events involved in the eastern Paleo-Tethyan closure. Results show that detrital spinels from the Upper Triassic Xinduqiao, Zhuwo, and Zagunao formations have variable concentrations of Cr 2 O 3 (24.36 -68.56 wt%), Al 2 O 3 (0.13 -39.17 wt%), MgO (0.20 -21.25 wt%), FeO T (11.15 -48.49 wt%), and TiO 2 (0.00 -4.66 wt%). They are geochemically similar to spinels from both ophiolites and stratiform intrusions, and affinitive to the counterparts from island-arc, supra-subduction zone, or mid-ocean ridge settings. Based on comparison with the spinel compositions from adjacent tectonic zones and in combination with previously published evidence from paleogeography, paleocurrent orientation, and geochronology, we propose the detrital spinels from the Upper Triassic sequence in the eastern Songpan-Ganzi Terrane were mainly recycled from the Lower -Middle Triassic strata in the West Qinling Terrane, with minor concentrations derived from the A 'nyemaqen ophiolites. This provenance inference presents a new insight into the closure time of the eastern Paleo-Tethys Ocean.

The Cenomanian-Turonian Oceanic Anoxic Event 2 (OAE 2, ca. 94 Ma) is characterized by a marked positive carbon isotope excursion (CIE) recorded in global marine basins. This CIE results from a global-scale increase in organic matter burial, facilitated by high productivity and seawater deoxygenation. To date, however, the precise pattern of changes in the burial rate of organic matter through the event has not been well constrained. In this work, we present a compilation of data from 42 globally distributed OAE 2 sites, as well as organic carbon isotope (S13Corg), total organic carbon (TOC), and trace element concentration data from a new OAE 2 interval in southern Tibet, China. In southern Tibet, the absence of redox-sensitive trace element enrichment through OAE 2 indicates prevailing oxic conditions. Organic carbon (OC) mass accumulation rate (MAR) at this site decreased from the lower part of the CIE to the upper part, in contrast to an approximate doubling of organic carbon MAR in the upper part observed globally. This result, coupled with detailed analysis of the compilation, shows that redox was a key factor controlling organic burial rates during OAE 2, with OC MAR scaling positively with increasing deoxygenation. Leveraging a biogeochemical model to simulate these data suggets that 5-20% of the seafloor became anoxic during OAE 2, and that this deoxygenation was accompanied by 100% to 200% increase in global seawater P concentration. Our findings indicate that during OAE 2, elevated nutrient levels may have resulted from enhanced recycling from sediments under reducing conditions, sustaining intensified primary production and subsequent organic carbon export and burial.

This special issue of Mesozoic is dedicated to the memory of a great specialist in carbonate sedimentology, Dr Juan Li, who passed away on July 19th, 2023. Juan Li sadly left us while logging the Paleocene-Eocene thermal maximum (PETM) interval in the Tibetan Himalaya. This special issue has collected contributions to Mesozoic–Cenozoic geological studies from the Qinghai-Tibet Plateau from colleagues, friends, and fellow scientists to express our remembrance and regret.

&lt;p&gt;The variations in carbon isotope (&amp;#948;&lt;sup&gt;13&lt;/sup&gt;C) values of the Aptian marine and terrestrial strata are globally comparable and regarded as an important tool for the stratigraphic correlation of the Aptian successions. The most remarkable feature of the &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C curve of the Aptian is an abruptly negative excursion, which characterizes the onset of the early Aptian Oceanic Anoxic Event (OAE 1a, ~121 Ma). However, the identification of OAE 1a equivalent level in the Tibetan Himalaya remains debatable. Based on previously well-established foraminiferal biostratigraphy, we provide a lower Aptian high-resolution &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C curve of bulk organic carbon from an expanded shale-dominated section, Chaqiela Section in the Tibetan Himalaya. The TOC/TN ratios of the studied section vary from 3 to 10, indicating that the organic matter is mainly sourced from marine plankton. Thus, we suggest that our results present the secular changes of &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C in the dissolve carbon pool of the shallow sea on the south margin of eastern Tethys. The lower Aptian &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C curve of the Chaqiela section is divided into eight segments, which can be well correlated to the representative sections in the western Tethys area.&lt;/p&gt; &lt;p&gt;In the lower part of the section, an interval of sharp negative carbon isotope excursion (CIE) of ~1 &amp;#8240; is observed, which is followed by recovery of the &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C values by a magnitude of ~2 &amp;#8240;. This short-term carbon perturbation is superimposed on the long-term decrease in &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C values of the early Aptian. The &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C profile at this interval perfectly records the diagnostic characteristics of the OAE 1a: negative (C3), positive (C4), steady (C5), and positive (C6) segments. Lacking covariations of &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C values with TOC/TN and TOC, and &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C and Al in this interval indicate that the &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C variations are not attributed to source changes of the organic matter. No obvious enrichments of the redox-sensitive major and trace elements indicate an oxic to sbuoxic condition during the sedimentation, it is in good agreement with the low C&lt;sub&gt;org&lt;/sub&gt;:P&lt;sub&gt;tot&lt;/sub&gt; ratios, but the slightly increase of C&lt;sub&gt;org&lt;/sub&gt;:P&lt;sub&gt;tot&lt;/sub&gt; ratios during the OAE 1a interval may imply a relatively oxygen-reducing trend and sustains till the end of OAE 1a. The paleoclimatic proxies imply a relatively warm and humid paleo-environment in mid-high latitudes (~50&amp;#176;S) of Tibetan Himalaya during this time interval, it is also testified by the moderate chemical weathering condition revealed by the A-CN-K ternary diagram.&lt;/p&gt;

Studies of geochemical proxies, such as carbonate d(18)O and TEX86, show that the Earth's climate has changed significantly during the Cretaceous Period. However, knowledge about the sea surface temperature (SST) history of the eastern Tethys is limited. Based on the calcareous nannofossil record of the Nirang section, Tethys Himalayas, this paper attempts to establish the biostratigraphic framework and SST evolution of the Cretaceous Period in the southern Tibet. A total of 131 species were identified from the studied succession. Twelve bioevents were recognized, allowing for early Albian to the early Campanian (CC8 to CC18 biozones) in the section. Meanwhile, a disconformity within 81-71 Ma was also identified. The SST evolution was analysed by the calcareous nannofossils modified temperature index (mTI), and the results reveal that the long-term SST changes in the Tethys Himalayas of southern Tibet experienced progressive warming from the early Albian to the early Turonian and the warm interval persisted until the early Campanian. Short-term warming and cooling events, e. g., rapid warming in the early and late Albian, subsequent cooling in the latest Albian and peak warmth at the Cenomanian-Turonian transition, are also recorded in the study area. The SST history of the Albian-Cenomanian in the eastern Tethys can be well correlated to the western Tethys (central Italy). However, the compilation of TEX86 data indicates substantial global cooling during the Coniacian to Campanian. This study suggests that the northward drift of the Indian continent towards the equator is likely to be responsible for the sustained warmth in the Tethys Himalayas from the middle Turonian to the early Campanian.